rs6000: More factoring of overload processing

rs6000: More factoring of overload processing

This patch continues the refactoring started with r12-6014.  I had previously
noted that the resolve_vec* routines can be further simplified by processing
the argument list earlier, so that all routines can use the arrays of arguments
and types.  I found that this was useful for some of the routines, but not for
all of them.

For several of the special-cased overloads, we don't specify all of the
possible type combinations in rs6000-overload.def, because the types don't
matter for the expansion we do.  For these, we can't use generic error message
handling when the number of arguments is incorrect, because the result is
misleading error messages that indicate argument types are wrong.

So this patch goes halfway and improves the factoring on the remaining special
cases, but leaves vec_splats, vec_promote, vec_extract, vec_insert, and
vec_step alone.

2022-02-02  Bill Schmidt  <wschmidt@linux.ibm.com>

gcc/
	* config/rs6000/rs6000-c.cc (resolve_vec_mul): Accept args and types
	parameters instead of arglist and nargs.  Simplify accordingly.  Remove
	unnecessary test for argument count mismatch.
	(resolve_vec_cmpne): Likewise.
	(resolve_vec_adde_sube): Likewise.
	(resolve_vec_addec_subec): Likewise.
	(altivec_resolve_overloaded_builtin): Move overload special handling
	after the gathering of arguments into args[] and types[] and the test
	for correct number of arguments.  Don't perform the test for correct
	number of arguments for certain special cases.  Call the other special
	cases with args and types instead of arglist and nargs.